I've finally sussed out my reservation here;

Certainly before settling on an E90, don't forget to try an RX-8.

Despite the thirst and the odd new engine, I'm sure the running costs will be favourable and you can pick them up for peanuts now, so depreciation's taken care of.

They are far more cramped and less practical than an E90, but that's the key to its advantage; it's sort of a four-seater MX-5/S2000 cross and therefore far more of a fun-to-drive car, which doesn't need a ridiculously big engine to achieve it.

There's also a supercharger kit if you are a bit mental...